Spout for pouch and plastic pouch with spout fixed thereto

ABSTRACT

The invention provides a spout for a pouch, which can be reliably heat-sealed with a plastic pouch body to provide an excellent gas-shielding capability for preventing gas permeation through the spout itself, and can be simply manufactured at a low cost without requiring complicated processes and special materials. In a spout for a pouch, comprising a tubular mouth part having a cap fitting portion and a seal part connected to a lower end portion of the mouth part for sealing with the pouch, the invention is featured in that a horizontal cross-sectional shape of the seal part is different in a height direction between an upper end portion and a lower end portion thereof, and an outer peripheral length of the horizontal cross-sectional shape is substantially equal at any position between the upper end portion and the lower end portion of the seal part.

FIELD OF THE INVENTION

The present invention relates to a spout for a pouch, which is fixed toa plastic pouch for containing beverages, foods, seasonings,pharmaceuticals, cosmetics, detergents, etc., and also related to aplastic pouch with the spout fixed thereto.

BACKGROUND OF THE INVENTION

A pouch with a spout, i.e., a pouch formed of a heat-sealed plastic filmand having a spout fixed to the opening portion of the pouch, is widelyused as means for containing beverages, foods, seasonings,pharmaceuticals, cosmetics, detergents, etc.

As a spout of such a plastic pouch, there is known a cylindrical spoutas shown in FIG. 16. When fixing a cylindrical spout 21 to a mouth partof a plastic pouch 22 by heat sealing, however, wrinkles 23 are causedin a plastic film constituting a pouch body 22 in areas on the oppositelateral sides of the spout 21 inserted in the pouch (see FIG. 16), whichcauses much difficulty in performing the heat sealing between the spoutand the pouch. Therefore, the following problems have been experienced.The spout cannot be fixed to the pouch at a desired level ofheat-sealing strength. The generation of the wrinkles deteriorates anouter appearance of the pouch filled with the contents. Stresses tend toconcentrate in the areas where the wrinkles have generated. Hence, inthe event of the pouch with the spout being dropped, for example, in astate filled with the contents, the pouch may rupture in those areas andthe contents may leak out of the pouch.

Aiming at overcoming the problems mentioned above and realizing reliableheat sealing between the spout and the body of the plastic pouch, it isproposed to form a seal part 32 of a spout 31, which is inserted in thepouch, as a boat-shaped portion 33 symmetrical in the left and rightdirection, as shown in FIG. 17.

With a plastic pouch 35 using that type of spout 31, the heat-sealingcapability between the spout 31 and the pouch body 35 is improved.However, because a plastic material (usually a polyolefin resin, such aspolyethylene and polypropylene, having a high heat-sealing capability)constituting the spout 31 has a low gas-shielding capability, theplastic pouch 35 has accompanied a drawback that gas flows between theinterior and the exterior of the pouch while permeating through theboat-shaped portion 33, as indicated by arrows in FIG. 17, whereby thecontents filled in the pouch 35 are oxidized and hence deteriorate.

A conceivable solution for preventing such a reduction of the gasshielding capability caused by the configuration of the spout itself isto form a gas barrier layer in the spout. However, even when acylindrical gas barrier layer 36 is formed in the spout as shown in FIG.18(A), gas cannot be prevented from permeating through the boat-shapedportion 33. Only when the gas barrier layer 36 is formed to cover acylindrical mouth part 34 in an upper portion of the spout and an entireupper surface of the boat-shaped portion 33 as shown in FIG. 18(B), gascan be prevented from permeating through the spout itself.

It is, however, very difficult to form the gas barrier layer having sucha complicated shape in the spout. Hence, that type of spout cannot bemanufactured with practically feasible cost and processes.

Accordingly, an object of the present invention is to solve the problemsset forth above and to provide a spout for a pouch, which can bereliably heat-sealed to a plastic pouch body to provide an excellentgas-shielding capability for preventing gas permeation through the spoutitself, and can be simply manufactured at a low cost without requiringcomplicated processes and special materials.

Another object of the present invention is to provide a plastic pouchwith such a spout, which has a more aesthetically pleasing outerappearance without wrinkles or the likes, an excellent gas-shieldingcapability, and a high heat-sealing strength.

DISCLOSURE OF THE INVENTION

As a result of conducting intensive studies, the inventors have foundthat the above objects can be achieved by devising the shape of a partof a spout, which is inserted in a pouch and fixed to a pouch body forsealing, and have accomplished the present invention based on thefinding.

More specifically, the present invention is constituted as follows:

1. A spout for a pouch, comprising a tubular mouth part having a capfitting portion and a seal part connected to a lower end portion of themouth part for sealing with the pouch, wherein a horizontalcross-sectional shape of the seal part is different in a heightdirection between an upper end portion and a lower end portion thereof,and an outer peripheral length of the horizontal cross-sectional shapeis substantially equal at any position between the upper end portion andthe lower end portion of the seal part.

2. A spout for a pouch according to 1, wherein an area surrounded by acontour of the horizontal cross-section of the seal part continuouslyincreases in a direction toward the lower end portion from the upper endportion of the seal part.

3. A spout for a pouch according to 1 or 2, wherein a horizontalcross-sectional shape of the seal part is circular or elliptic in theupper end portion thereof and is boat-like symmetrical in the left andright direction in the lower end portion thereof.

4. A spout for a pouch according to any one of 1 to 3, wherein wingpieces each having a thickness increasing in a direction toward thelower end portion from the upper end portion thereof are symmetricallyprovided on opposite sides of the seal part.

5. A spout for a pouch according to any one of 1 to 4, whereinouter-peripheral lower end portions of the seal part are rounded.

6. A spout for a pouch according to any one of 1 to 5, wherein atongue-shaped projection is provided at a lower end portion of the sealpart.

7. A spout for a pouch according to any one of 1 to 6, wherein a gasbarrier layer is provided at least in the tubular mouth part of thespout.

8. A spout for a pouch according to any one of 1 to 7, wherein abar-like member is provided to extend downward from the seal part.

9. A spout for a pouch according to any one of 1 to 8, wherein a rib isprovided on the seal part.

10. A spout for a pouch according to any one of 1 to 9, wherein a capequipped with a heat sealable lid is fitted to the mouth part of thespout, the cap having means to peel off the heat sealed lid from themouth part of the spout when the cap is opened.

11. A pouch with a spout, wherein a spout for a pouch according to anyone of 1 to 10 is fixed to an opening portion of the pouch by heatsealing.

12. A pouch with a spout according to 11, wherein the spout is fixed tothe opening portion of the pouch such that the upper end portion of theheat-sealed part of the spout is arranged inward of the pouch from theupper end portion of the pouch body.

In the present invention, the term “outer peripheral length” of thehorizontal cross-section of the seal part of the spout fixed to thepouch for sealing means a length defined as follows:

1) When the spout has, as shown in FIGS. 1 to 3, a pair of wing pieces6, 6 formed on opposite sides of a barrel 5 of a seal part 4 and havingthe same width from an upper end portion to a lower end portion thereof,the “outer peripheral length” means an actual length of the horizontalcross-section of the seal part 4, i.e., a length from a1 to a3 via a2 inFIG. 3(A), a length from b1 to b3 via b2 in FIG. 3(B), and a length fromc1 to c3 via c2 in FIG. 3(C).

2) When the spout has, as shown in FIGS. 9 to 11, no wing pieces 6 onopposite sides of the barrel 5 of the seal part 4, or when the spout haswing pieces 6 in each of which the width at the upper end portion of thewing piece 6 differs from the width at the lower end portion of the wingpiece 6 (usually, as shown in FIG. 12, the width of the wing piece 6 atthe upper end portion is smaller than that at the lower end portion),the “outer peripheral length” means a length defined below. Assumingstraight lines (hereinafter referred to as “imaginary lines”) L1 and L2drawn to vertically rise from opposite-side lower end portions of theseal part 4 as shown in FIGS. 9 and 10, the “outer peripheral length”means a length (hereinafter referred to as an “imaginary outerperipheral length”) from the imaginary line L1 to the imaginary line L2via an outer periphery of the seal part 4 of the spout 1, i.e., a lengthfrom d1 to d3 via one side d2 of the seal part 4 in FIG. 10(D), a lengthfrom e1 to e3 via one side e2 of the seal part 4 in FIG. 10(E), and alength from f1 to f3 via one side f2 of the seal part 4 in FIG. 10(F).

Also, the expression that lengths are “substantially equal” means thatthe lengths are within the range of ±10% of an average value or so.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows one example of a spout for a pouch according to the presentinvention,

FIG. 2 is a vertical cross-sectional view of the spout shown in FIG. 1,and

FIG. 3 is a horizontal cross-sectional view of the spout shown in FIG.1.

FIG. 4 is a perspective view showing a standing pouch to which the spoutshown in FIG. 1 is fixed,

FIG. 5 is an enlarged cross-sectional view of a portion of the standingpouch shown in FIG. 4 to which the spout is fixed, and

FIG. 6 is a schematic side cross-sectional view of the standing pouchshown in FIG. 4.

FIG. 7 shows another example of the spout for the pouch according to thepresent invention.

FIG. 8 shows still another example of the spout for the pouch accordingto the present invention.

FIG. 9 shows still another example of the spout for the pouch accordingto the present invention,

FIG. 10 is a horizontal cross-sectional view of the spout shown in FIG.9, and

FIG. 11 is a vertical cross-sectional view of the spout shown in FIG. 9.

FIG. 12 shows still another example of the spout for the pouch accordingto the present invention.

FIG. 13 shows still another example of the spout for the pouch accordingto the present invention.

FIGS. 14 and 15 show still another example of the spout for the pouchaccording to the present invention, in which a heat-sealabe-lid equippedcap is fitted to a mouth part of the spout.

FIGS. 16 and 17 show a conventional pouch to which a known spout for thepouch is fixed.

FIG. 18 is a schematic view showing a state of gas permeation throughthe spout itself for the pouch.

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described below withreference to the drawings.

FIGS. 1 to 3 show one example of a spout for a pouch according to thepresent invention. FIG. 1 is a front view of the spout, and FIG. 2 is avertical cross-sectional view of the spout shown in FIG. 1. FIG. 3 is ahorizontal cross-sectional view of the spout shown in FIG. 1. Morespecifically, (A), (B) and (C) of FIG. 3 show horizontal cross-sectionstaken along the lines AA, BB and CC in FIG. 1, respectively.

Further, FIG. 4 is a perspective view showing a standing pouch to whichthe spout shown in FIG. 1 is fixed, and FIG. 5 is an enlargedcross-sectional view of a portion of the standing pouch shown in FIG. 4to which the spout is fixed. FIG. 6 is a schematic side cross-sectionalview of the standing pouch shown in FIG. 4.

The spout 1 for a pouch, shown in FIG. 1, comprises a cylindrical mouthpart 3 having a screwed portion 2 formed on its outer periphery forfitting with a cap (not shown) and a passage 7 formed therein, and aseal part 4 provided at a lower end portion of the mouth part 3 forsealing with a plastic pouch. The seal part 4 fixed to the plastic pouchby heat sealing comprises a barrel 5 formed such that an outercross-sectional shape of its upper end portion is circular and across-sectional shape of its lower end portion is boat-like symmetricalin the left and right direction, and a pair of wing pieces 6, 6 providedon opposite sides of the barrel 5 and each having a thickness graduallyincreasing in a direction from the upper end portion toward the lowerend portion thereof. In addition, the seal part 4 has an outerconfiguration formed such that a thickness of the seal part 4 graduallyand continuously increases in a direction toward the lower end portionfrom the upper end portion thereof and, as shown in (A), (B) and (C) ofFIG. 3, an area surrounded by a contour of its horizontal cross-sectioncontinuously increases in a direction toward the lower end portionrepresented by (C) from the upper end portion represented by (A).Further, the wing pieces 6 are formed in thickness gradually decreasingtoward opposite side ends.

In the spout 1 thus constructed, an outer peripheral length of thehorizontal cross-section of the seal part 4 fixed to the plastic pouchby sealing, i.e., a length from a1 to a3 via a2 in FIG. 3(A), a lengthfrom b1 to b3 via b2 in FIG. 3(B), and a length from c1 to c3 via c2 inFIG. 3(C), are substantially equal at any different levels of the sealpart 4. Here, the expression “substantially equal” means that thelengths are within the range of ±10% of an average value or so. In orderto minimize wrinkles caused when the seal part 4 is fixed to the plasticpouch by heat sealing, however, the lengths are more preferably keptwithin the range of ±5% of an average value. By setting the shape andsize of the spout 1 as described above, when the spout 1 is inserted inan opening portion of a pouch 11 and fixed to it by heat sealing asshown in FIGS. 4 and 5, the plastic film constituting the pouch 11 andthe spout 1 are brought into a smoother contact with each other. It istherefore possible to prevent wrinkles from being caused upon the heatsealing, and to avoid stresses from being concentrated on near a joinedportion between the plastic film and the spout 1. In addition, byproviding the seal part in the form of very thin wings, i.e., the wingpieces 6, which extend along spout end portions, it is possible toeffectively fill up small voids that tend to generate upon the heatsealing between the spout and the pouch in areas where the spout endportions and the pouch meet each other.

Further, as shown in FIG. 6, the standing pouch with the spout 1 fixedthereto has a smooth outer appearance and a much improved standingposture. As a result, a commodity value of the pouch filled with thecontents is increased.

In the spout 1 of this example, a gas barrier layer 8 is provided as anintermediate layer inside a cylindrical mouth part 3 of the spout 1 soas to ensure a gas shielding capability of the plastic pouch 11 to whichthe spout 1 is fixed.

With the spout 1 thus constructed, the gas barrier layer 8 serves toshut off gas permiation through the mouth part 3 of the spout 1.Further, as shown in FIG. 3(A), since the seal part 4 fixed to the pouch11 by heat sealing has a very small cross-sectional area in its upperend portion, gas permeation through the spout 1 itself can be greatlyreduced.

Further, as shown in FIG. 5, when fixing the spout 1 and the pouch 11together by heat sealing, the spout 1 is arranged such that the upperend portion of the seal part 4 of the spout 1 is positioned completelyinside the pouch 11 and a heat-sealed area 12 where the opposite-sideplastic films constituting the pouch 11 are joined to each other by theheat sealing is formed above the seal part 4. With such an arrangement,gas permeation through the spout 1 itself can be perfectly shut off.

FIG. 7 shows another example of the spout for the pouch according to thepresent invention. More specifically, FIG. 7(A) is a front view of thespout, and FIG. 7(B) is a vertical cross-sectional view taken along theline XX in FIG. 7(A).

In the spout 1 of this example, the lower end portion of the seal part 4is rounded at its outer periphery as denoted by R. The otherconstruction of the spout 1 of this example is the same as that of thespout shown in FIG. 1. When a pouch fixed with the spout 1 of thisexample and filled with the contents is dropped, the pouch is avoidedfrom breaking at the lower end portion of the seal part 4 of the spout1. Consequently, the strength of the pouch with the spout againstdropping can be greatly increased.

FIG. 8 shows still another example of the spout for the pouch accordingto the present invention. More specifically, FIG. 8(A) is a front viewof the spout, and FIG. 8(B) is a vertical cross-sectional view takenalong the line YY in FIG. 8(A).

In the spout 1 of this example, the lower end portion of the seal part 4is rounded at its outer periphery as denoted by R and are provided withtongue-shaped projections 9. Also, the passage 7 provided in the spout 1is formed so as to gradually spread in the barrel 5 in match with theouter configuration thereof. Further, hanger flanges 10, 10 each havinga substantially rectangular plan shape are provided on an outerperiphery of the mouth part 3 of the spout 1 to serve athes for carryingthe pouch in a hanging state while being supported at the spout. When apouch fixed with the spout 1 of this example and filled with thecontents is dropped, the tongue-shaped projections 9 are flexed todevelop a damping action, and therefore the pouch is avoided frombreaking at the lower end portion of the seal part 4 of the spout 1.Consequently, the strength of the pouch with the spout against droppingcan be further increased.

In the illustrated example, the projections 9 are formed with athickness gradually decreasing toward its fore end so that thetongue-shaped projections 9 are apt to more easily flex. As a matter ofcourse, however, the thickness of the tongue-shaped projections 9 is notspecifically required to be changed.

The tongue-shaped projection 9 develops the effects of increasing thestrength of the pouch with the spout against dropping, and of preventingthe plastic film constituting the pouch body from causing a blockagewhen the contents are poured, thereby improving a capability of pouringthe contents.

FIGS. 9 to 11 show still another example of the spout for the pouchaccording to the present invention. More specifically, FIG. 9 is a frontview of the spout, FIG. 10 is a horizontal cross-sectional view of thespout, and FIG. 11 is a vertical cross-sectional view of the spout. (D),(E) and (F) of FIG. 10 are horizontal cross-sectional views taken alongthe lines DD, EE and FF in FIG. 9, respectively.

In the spout 1 of this example, the seal part 4 is constituted by onlythe barrel 5 connected adjacent to the lower portion of the mouth part 3without providing the wings 6 in the seal part 4 fixed to the plasticpouch by heat sealing. Further, a gas barrier layer 8 is formed byproviding a vapor-deposited metal layer over an entire surface of thepassage 7 extending from an upper end of the mouth part 3 of the spoutto a lower end of the seal part 4 (i.e., over an entire inner peripheralsurface of the spout 1). The other construction of the spout 1 of thisexample is the same as that of the spout shown in FIG. 1.

In the spout 1 of this example, assuming straight lines (hereinafterreferred to as “imaginary lines”) L1 and L2 drawn to vertically risefrom opposite-side lower end portions of the seal part 4, a length(hereinafter referred to as an “imaginary outer peripheral length”) fromthe imaginary line L1 to the imaginary line L2 via an outer periphery ofthe horizontal cross-section of the seal part 4 of the spout 1, i.e., alength from d1 to d3 via one side d2 of the seal part 4 in FIG. 10(D), alength from e1 to e3 via one side e2 of the seal part 4 in FIG. 10(E),and a length from f1 to f3 via one side f2 of the seal part 4 in FIG.10(F), are substantially equal at any different levels of the seal part4.

By setting the imaginary outer peripheral length of the spout 1 in sucha manner, the heat-sealing capability between the spout 1 and theplastic pouch can be further improved. The spout 1 of this example canalso provide similar advantageous effects to those obtainable with thespout shown in FIG. 1.

FIG. 12 shows still another example of the spout for the pouch accordingto the present invention. More specifically, FIG. 12(A) is a front viewof the spout, and FIG. 12(B) is a vertical cross-sectional view takenalong the line ZZ in FIG. 12(A). In the spout 1 of this example, theseal part 4 is constructed by providing a pair of flat wings 6, 6, eachof which has a substantially constant thickness, on opposite lateralsides of a truncated cone-shaped barrel 5 having a substantiallyconstant thickness. Further, hanger flanges 10, 10 each having asubstantially rectangular plan shape are formed at a root of the mouthpart 3 of the spout 1, and ribs 13 are provided on an outer periphery ofthe barrel 5 and on the wings 6 for improving the heat-sealingcapability between the spout 1 and the pouch.

While, in the illustrated example, the ribs 13 are provided to extend inthe horizontal direction parallel to each other, it is needless to saythat the arrangement of the ribs 13 can be modified as required. Forexample, the ribs 13 may be provided to extend in the verticaldirection.

Comparing with the conventional spout, shown in FIG. 17, in which thehorizontal cross-sectional shape is the same at the upper end portionand the lower end portion, the spout for the pouch according to thepresent invention, shown in the examples described above, has theimproved effect of preventing a phenomenon that the film constitutingthe pouch body is bent to cause a blockage at a position just below thespout when the contents are poured.

In the conventional spout for the pouch, it is also proposed to providea bar-like member extending downward from the spout for preventing theoccurrence of a blockage and ensuring a capability of pouring thecontents. With the spout for the pouch according to the presentinvention, however, such a bar-like member can be omitted and hence anamount of raw material for producing the spout can be cut down. Withoutthe bar-like member, the pouch can be folded into a smaller sizecorrespondingly. This brings about such advantages as (1) the remainingamount of the contents can be reduced (i.e., a consumer can drink thecontents up to the last), and (2) because the pouch can be folded into asmaller size when discarded after the use, the volume of pouchesdiscarded in folded states can be reduced. As a matter of course, asshown in FIG. 13, to ensure a more reliable capability of pouring thecontents, the bar-like member may be provided to extend downward fromthe spout.

FIG. 13 is a front view showing still another example of the spoutaccording to the present invention.

In the spout 1 of this example, a bar-like member 14 is formed to extenddownward from the seal part 4 and to be inserted in the pouch. Further,hanger flanges 10 each having a rectangular plan shape are provided onan outer periphery of the cylindrical mouth part 3 to serve athes forcarrying the pouch in a hanging state while being supported at thespout. Although, in the illustrated example, two hanger flanges 10 areprovided, three or more hanger flanges may be provided instead. Theother construction of the spout 1 of this example is the same as that ofthe spout shown in FIG. 1.

With the spout 1 of this example, the capability of pouring the contentsfilled in the pouch is improved with the provision of the bar-likemember 14. The bar-like member 14 can be modified as desired, forexample, by forming recesses, projections and/or holes therein, and itssize can be selected on the case-by-case basis. The spout 1 of thisexample can also provide similar advantageous effects to thoseobtainable with the spout shown in FIG. 1.

In each of the examples described above, the mouth part is formed into acylindrical shape so that a screwed cap is fitted to the mouth part ofthe spout. However, when fixing a cap to the spout by other means, e.g.,by engaging a recess and a projection with each other instead ofscrewing the cap, the mouth part of the spout and the upper end portionof the seal part may be formed to have any other suitablecross-sectional shape such as an elliptic shape. Alternatively, the capmay be constituted as a hinge cap.

FIGS. 14 and 15 show still another example of the spout for the pouchaccording to the present invention. Regarding this example, FIG. 14 isan overall view showing one example in which a cap equipped with a heatsealable lid is fitted to a mouth part of the spout of the presentinvention. FIG. 15(a) is a cross-sectional view of the cap equipped withthe heat sealable lid, FIG. 15(b) is a cross-sectional view of the mouthpart of the spout when the cap equipped with the heat sealable lid isemployed, FIG. 15(c) is a cross-sectional view showing a state in whichthe cap equipped with the heat sealable lid is fitted to the mouth partof the spout, FIG. 15(d) is a cross-sectional view showing anotherexample of a heat sealable lid.

In the spout 1 of this example, by externally heating the spout afterfitting a heat-sealable-lid equipped cap 41 to the mouth part 3 of thespout, the mouth part 3 of the spout can be enclosed by a heat sealablelid 42. When opening the spout, it is just required to rotate a capbody. With the rotation of the cap body, a peeling-off means constitutedas an annular projection 43 provided in the cap body pushes up a portion44 of the heat sealed lid 42 projecting out of the mouth part 3 of thespout, whereupon the heat sealed lid 42 is peeled off from the mouthpart 3 of the spout, thus enabling the spout to be opened with oneaction. By using such an opening mechanism, the heat sealed lid 42 canbe easily peeled off and the spout can be easily opened by fingers withno need of applying a large opening torque.

The heat-sealable-lid equipped cap 41 comprises, by way of example, acap body made up of a top wall 45 and a skirt wall 46 which is extendeddownward from the top wall 45 and has a screwed portion 47 formed on itsinner peripheral surface to be meshed with the screwed portion 2 of themouth part 3 of the spout, and the heat sealable lid 42 fitted to andsupported at a region between an upper end of the screwed portion on theinner side of the cap body and an inner peripheral portion of the topwall. The heat sealable lid 42 has a heat-sealable layer formed at leaston its lower surface, and is made of an elastic material having theprojected portion 44 which has an outer diameter larger than that of themouth part 3 of the spout and is projected out of the outer periphery ofthe mouth part 3 of the spout. The peeling-off means constituted as theannular projection 43 engageable with the projected portion 44 of theheat sealable lid 42 is provided on an inner peripheral surface of theskirt wall 46. By screwing the cap body over the mouth part 3 of thespout and heating it, the heat sealable lid 42 is sealed to a topopening end of the spout. When opening the spout, the cap body isunscrewed from the mouth part 3 of the spout, whereupon the heat sealedlid 42 is peeled off by the peeling-off means.

The heat sealable lid 42 can be constituted as a multilayered sheet madeup of at least a support layer which is formed on its upper surface andhas rigidity, and a sealing layer which is formed on its lower surfaceand capable of being fixed to the opening top end of the spout by heatsealing. When the heat sealable lid 42 is constituted as a multilayeredsheet including a metal foil inserted between the support layer and thesealing layer, the metal layer is heated by high-frequency inductionheating to produce heat so that the sealing layer can be effectivelyheat-sealed to the opening top end of the spout by the produced heat.The shape of the heat sealable lid 42 is not limited to a disk-like one.As shown in FIG. 15(d), by way of example, the heat sealable lid 42 maybe formed into a shape having an annular intermediate leg 48 fitted tothe inner peripheral surface of the mouth part 3 of the spout.

As the peeling-off means for peeling off the heat sealed lid 42 uponunscrewing of the cap body when the spout is opened, it is effective toform one annular projection 43 having an inner diameter smaller than theouter diameter of the heat sealed lid 42, or to form a plurality ofprojections. However, the peeling-off means is not limited to thoseexamples, and an upper end of the screwed portion formed on the innerperipheral surface of the skirt wall 46 may serve also as thepeeling-off means.

The heat sealable lid 42 is constituted as an elastic member which hasat least the sealing layer and the support layer, and which develops anadhesion strength with a material of the opening top end of the spoutessentially in the range of 1 to 25 N per 15-mm width in terms ofT-peeling strength. Further, a thickness t (mm) and a modulus of bendingelasticity M (Mpa) of the heat-sealed layer and the support layer areset in the range of 30<t×M<3000. By so forming the heat sealable lid 42,it can be satisfactorily peeled off from the opening top end of thespout when the spout is opened. The heat sealing strength must beselected so as to simultaneously provide an opening capability and asealing capability at satisfactory levels. From this point of view, theT-peel strength of the heat-sealed portion is preferably held in theabove-mentioned range. If the T-peel strength is smaller than the lowerlimit, there occurs a fear in the sealing capability. If the T-peelstrength is larger than the upper limit, the peel strength is too highand a larger torque is required for removing the screwed cap when thespout is opened, thus resulting in deterioration of the openingcapability. On the other hand, if t×M is not more than 30, the rigidityof the sealing lid is too small and the sealing lid is deformed whenpeeling off it, and hence a force required for breaking the sealedportion cannot be developed. Conversely, if t×M is not less than 3000,the sealing lid is hardly deformed when peeling off it, and hence aforce for breaking the sealed portion must be applied to the entiresealing lid surface, whereby the unsealing strength is increased.

As materials of the spout of the present invention, thermoplastic resinsare used to which the plastic film constituting the pouch can cohere byheat sealing.

Examples of such thermoplastic resins include polyolefins such aspolypropylene, a propylene-ethylene copolymer, crystalline polybutene-1,crystalline poly 4-metylpentene-1, low-, medium- or high-densitypolyethylene, linear low-density polyethylene, an ethylene-vinyl acetatecopolymer (EVA), an ethylene-acrylic acid copolymer (EAA), anethylene-ethyl acrylate copolymer (EEA), and an ion cross-linked olefincopolymer (ionomer); aromatic vinyl polymers such as polystyrene and astyrene-butadiene copolymer; vinyl halide polymers such as polyvinylchloride and vinylidene chloride resin; nitrile polymers such as anacrylonitrile-styrene copolymer and an acrylonitrile-styrene-butadienecopolymer; polyamides such as nylon 6, nylon 66, and para- ormetaxylylene adipamide; polyesters such as polyethylene terephthalate,polybutylene terephthalate, polytetramethylene terephthalate,poly-1,4-cyclohexane dimethylene terephthalate, polyethylenenaphthalate; various kinds of polycarbonates; and polyacetals such aspolyoxymethylene.

Particularly preferable ones are, for example, polyolefin resins such aslow-density polyethylene, linear low-density polyethylene,medium-density polyethylene, high-density polyethylene, polypropylene,and a propylene-ethylene copolymer. The spout of the present inventioncan be molded by any of known methods, for example, injection moldingand compression molding.

The gas barrier layer formed in the spout is constituted by, e.g., a gasshielding resin layer made of polyvinylidene chloride resin, saponifiedEVA, nylon, or a cyclic olefin copolymer; a resin layer having avapor-deposited film of aluminum, silicon oxide, or another metal oxide;a resin layer containing clay minerals; and a foil of a metal such asaluminum.

The gas barrier layer can be formed in the spout by any of knownmethods, for examples, co-injection molding, multi-layer compressionmolding, multicolor molding, and vapor deposition.

Further, as the plastic film constituting the pouch, to which the spoutis fixed, a single-layer film made of thermoplastic resin having aheat-sealing capability can be used as well as a multilayered film madeof two or more layers, i.e., a pouch inner layer made of such athermoplastic resin film having a heat sealing capability and one ormore other films laminated on the inner layer.

The thermoplastic resin film having a heat sealing capability can bemade of thermoplastic resins, for example, polyolefins such aspolypropylene, a propylene-ethylene copolymer, crystalline polybutene-1,crystalline poly 4-metylpentene-1, low-, medium- or high-densitypolyethylene, linear low-density polyethylene, an ethylene-vinyl acetatecopolymer (EVA), an ethylene-acrylic acid copolymer (EAA), anethylene-ethyl acrylate copolymer (EEA), and an ion cross-linked olefincopolymer (ionomer); aromatic vinyl copolymers such as polystyrene and astyrene-butadiene copolymer; vinyl halide polymers such as polyvinylchloride and vinylidene chloride resin; nitrile polymers such as anacrylonitrile-styrene copolymer and an acrylonitrile-styrene-butadienecopolymer; polyamides such as nylon 6, nylon 66, and para- ormetaxylylene adipamide; polyesters such as polyethylene terephthalate,polybutylene terephthalate, polytetramethylene terephthalate,poly-1,4-cyclohexane dimethylene terephthalate, polyethylenenaphthalate; various kinds of polycarbonates; and polyacetals such aspolyoxymethylene.

Particularly preferable materials are, for example, olefin-based resinssuch as low-density polyethylene, linear low-density polyethylene,medium-density polyethylene, high-density polyethylene, polypropylene, apropylene-ethylene copolymer, an ethylene-vinyl acetate copolymer, andolefin resins graft-modified with ethylenically unsaturated carboxylicacids or anhydrides thereof; ionomer resins; polyamide or copolyamideresins having relatively low melting points or low softening points; andpolyester or copolyester resins.

In the case of employing a multilayered film as the plastic filmconstituting the pouch, the multilayered film is formed by using, as aninner layer of the pouch, the above-mentioned thermoplastic resin filmhaving a heat healing capability and laminating one or more other filmson it, as required, with an adhesive layer interposed between theadjacent two films.

As materials of the adhesive layer, adhesive resins are employed whichare selected from among polyethylene imine resins, alkyl titanateresins, polyester-isocyanate resins, urethane resins, epoxy resins,polyether resins, and olefin-based resins to which polar groups areintroduced.

The film laminated on the resin having a heat-sealing capability is notlimited to a particular one, but includes any suitable one of materialsusually employed for the pouch. While any of the above-mentionedmaterials suitable for the resin having a heat-sealing capability can beemployed as a material for the laminated film, it is preferable toselect a resin having a higher melting point than that of the resin usedas the inner layer.

As other examples of the film, a composite film formed by laminating afoil of a metal such as aluminum, paper, or cellophane with one or moreof the above-mentioned plastic film is also usable. In particular, whenthe contents require the pouch to have a gas shielding capability, it ispreferable to employ a multilayered film including any of a resin layermade of polyvinylidene chloride resin, saponified EVA, nylon, or acyclic olefin copolymer; a resin layer having a vapor-deposited film ofaluminum, silicon oxide, or another metal oxide; a resin layercontaining clay minerals; and a foil of a metal such as aluminum.

Films made of foams of various synthetic resins can be further used forthe purpose of giving heat insulation, rigidity and other desiredproperties to the film constituting the pouch. In addition, it is alsopossible to use films made of various synthetic resins in whichinorganic substances, such as alumina, silica, titanium oxide, calciumcarbonate, carbon and talc, glass fibers, or the likes are mixed.

Layer structure of the multilayered film suitable for constituting thepouch of the present invention are, for example, biaxially orientedpolyethylene terephthalate (PET: outer layer)/non-oriented linearlow-density polyethylene (LLDPE: inner layer), biaxially oriented nylon(outer layer)/LLDPE (inner layer), biaxially oriented PET (outerlayer)/aluminum foil (intermediate layer)/LLDPE (inner layer), biaxiallyoriented nylon (outer layer)/aluminum foil (intermediate layer)/LLDPE(inner layer), biaxially oriented PET (outer layer)/biaxially orientednylon (intermediate layer)/LLDPE (inner layer), biaxially oriented PET(outer layer)/aluminum foil (intermediate layer)/biaxially orientednylon (intermediate layer)/LLDPE (inner layer).

Also, when the pouch is employed in applications requiringhigh-temperature treatment such as heat treatment under high pressure, amultilayered film containing non-oriented polypropylene (PP) as an innerlayer can be used, which includes, for example, biaxially oriented PET(outer layer)/aluminum foil (intermediate layer)/non-orientedpolypropylene (PP: inner layer), biaxially oriented PET (outerlayer)/biaxially oriented nylon (intermediate layer)/aluminum foil(intermediate layer)/non-oriented PP (inner layer), biaxially orientedPET (outer layer)/non-oriented PP (inner layer), biaxially orientednylon (outer layer)/non-oriented PP (inner layer), biaxially orientednylon (outer layer)/aluminum foil (intermediate layer)/non-oriented PP(inner layer), biaxially oriented PET with a vapor-deposited inorganicoxide (outer layer)/non-oriented PP (inner layer), and biaxiallyoriented nylon with a vapor-deposited inorganic oxide (outerlayer)/non-oriented PP (inner layer).

An adhesive layer selected from among the adhesive resins mentionedabove is interposed between adjacent layers of such a multilayered film.

Whether the plastic film should be formed of a single layer or not, andwhat kind of layer structure should be employed for the plastic film areselected depending on properties of the contents filled in the pouch.The plastic film can be manufactured by any of ordinary methods such ascasting, T-dieing, calendering, and inflation. Also, the multilayeredfilm can be manufactured by any of ordinary methods such as drylamination of preformed films, coating on a base film, and co-extrusion.

The present invention will be described in more detail below inconnection with a practical example, but the present invention is in noway restricted by the following example.

EXAMPLE 1

A spout having a shape shown in FIG. 12 was manufactured throughcompression molding of polypropylene. The spout was dimensioned suchthat the overall height was 45 mm, the height of a seal part was 17 mm,the width of a lower end of the seal part was 24 mm, an upper end of theseal part had a circular cross-section with a diameter of 11.2 mm, thethickness of the seal part was 1.4 mm, and the thickness of a fittingportion of the cylindrical mouth part to the cap was 1.0 mm.

A multilayered film made of 12 μm-thick polyethylene terephthalate/15μm-thick biaxially oriented nylon/7 μm-thick aluminum alloy foil/50μm-thick polypropylene in this order from the outer layer side was usedas an envelope material constituting a pouch body. The multilayered filmwas heat-sealed to the manufactured spout after arranging the spout, asshown in FIGS. 4 and 5, such that the upper end of the seal part of thespout was positioned inside an upper end of the pouch body. Thus,standing pouch with the spout was manufactured which had a height of 140mm, a width of 90 mm, and a bottom gusset width of 25 mm.

COMPARATIVE EXAMPLE 1

A standing pouch with a spout was manufactured in the same manner as inExample 1 except for using a commercially available spout made ofpolypropylene and having a shape shown in FIG. 17. The spout having aboat-like shape was dimensioned such that the overall height was 36 mm,the height of a seal part was 8 mm, and the cross-section of the sealpart was 11.3-mm long×19.5-mm wide. A liquid passage with a diameter of8 mm was formed at the center of the spout.

After replacing atmospheres in the standing pouches with the spoutsobtained in Example 1 and Comparative Example 1 by nitrogen gas, a topsurface of a pouring port of each spout was enclosed by heat sealingwith a multilayered film made of a 7 μm-thick aluminum alloy foil/50μm-thick polypropylene. These pouches were preserved under conditions of30° C.-80% R.H., and an amount of oxygen permeating into the pouch wasmeasured with gas chromatography. Table 1 given below shows the measuredresults calculated in terms of the pouch with the content volume of 150ml. TABLE 1 Amount of Permeating Oxygen [ml/pouch] Beginning of After 1After 2 After 1 preservation week weeks month Example 1 0 0.072 0.1490.305 Com. Ex. 1 0 0.087 0.181 0.379

As apparent from Table 1, according to the spout of the presentinvention, the amount of oxygen permeating into the pouch can beminimized in comparison with that permeating into the pouch through theboat-like portion of the conventional spout. While, in Example 1described above, a gas barrier layer is not provided in the cylindricalmouth part of the spout, the gas shielding capability of the spout canbe further improved by providing such a gas barrier layer.

INDUSTRIAL APPLICABILITY

According to the spout of the present invention, since the plastic filmconstituting the pouch and the spout are brought into a smoother contactwith each other, it is possible to prevent wrinkles from being causedupon the heat sealing, and to avoid stresses from being concentrated onnear a joined portion between the plastic film and the spout. Hence, theheat sealing between the plastic pouch body and the spout can beperformed with higher reliability.

In addition, the spout of the present invention is able to prevent aphenomenon that the film constituting the pouch body is bent to cause ablockage inside the pouch at a position just below the spout when thecontents are poured from the pouch with the spout.

Further, merely by providing a cylindrical gas barrier layer in themouth part of the spout, it becomes possible to prevent gas permeationthrough the spout itself, and to increase the gas shielding capability.Additionally, the spout of the present invention can be simplymanufactured at a low cost without requiring complicated processes andspecial materials.

In particular, when the spout of the present invention is applied to astanding pouch, the pouch has a smoother outer appearance, a standingposture of the pouch is noticeably improved, and a commodity value ofthe pouch filled with the contents can be increased.

1. A spout for a pouch, comprising a tubular mouth part having a capfitting portion and a seal part connected to a lower end portion of themouth part for sealing with the pouch, wherein a horizontalcross-sectional shape of the seal part is different in a heightdirection between an upper end portion and a lower end portion thereof,and an outer peripheral length of the horizontal cross-sectional shapeis substantially equal at any position between the upper end portion andthe lower end portion of the seal part.
 2. A spout for a pouch accordingto claim 1, wherein an area surrounded by a contour of the horizontalcross-section of the seal part continuously increases in a directiontoward the lower end portion from the upper end portion of the sealpart.
 3. A spout for a pouch according to claim 1, wherein a horizontalcross-sectional shape of the seal part is circular or elliptic in theupper end portion thereof and is boat-like symmetrical in the left andright direction in the lower end portion thereof.
 4. A spout for a pouchaccording to claim 1, wherein wing pieces each having a thicknessincreasing in a direction toward the lower end portion from the upperend portion thereof are symmetrically provided on opposite sides of theseal part.
 5. A spout for a pouch according to claim 1, whereinouter-peripheral lower end portions of the seal part are rounded.
 6. Aspout for a pouch according to claim 1, wherein a tongue-shapedprojection is provided at a lower end portion of the seal part.
 7. Aspout for a pouch according to claim 1, wherein a gas barrier layer isprovided at least in the tubular mouth part of the spout.
 8. A spout fora pouch according to claim 1, wherein a bar-like member is provided toextend downward from the seal part.
 9. A spout for a pouch according toclaim 1, wherein a rib is provided on the seal part.
 10. A spout for apouch according to claim 1, wherein a cap equipped with a heat sealablelid is fitted to the mouth part of the spout, the cap having means topeel off the heat sealed lid from the mouth part of the spout when thecap is opened.
 11. A spout having an opening portion, wherein a spoutfor a pouch according to claim 1 is fixed to the opening portion of thepouch by heat sealing.
 12. A pouch with a spout according to claim 11,wherein the spout is fixed to the opening portion of the pouch such thatthe upper end portion of the heat-sealed part of the spout is arrangedinward of the pouch from the upper end portion of the pouch body.